Municipal Composting Study

Introduction: The City of Ellsworth has been working off and on for years toward establishing a municipal composting facility. Seafood & blueberry processing residuals, yard waste and septic sludge are obvious candidates for processing into a usable and perhaps commercially valuable product instead of using the current methods of disposal. Other materials such as post-consumer food scraps may also be composted, but require special handling and strict quality control. Notes compiled below were gathered by Sustainable Ellsworth and staff.

 

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Possible Sites: These and other sites have been considered...

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1. The City Reed Bed Parcel -- This 2.3 -acre lot (tax map 50, lot 29) and an adjacent 1.55-acre lot owned by the City are in the Industrial Park and are very convenient to the Ellsworth Transfer Station and an adjacent private transfer station. The site contains the reed bed which could be used to capture and treat run off from the paved composting area. Of the 4+ acres, about half would be available for a composting pad. The site is currently used as an emergency stand-by disposal area for municipal wastewater sludge.

Ellsworth Reed Bed Aerial Map (PDF) -- Reed Bed Cross-Section (PDF) -- Reed Bed Soils Study

2. The Old City Land-fill Site -- This 33-acre tract (tax map 35, lots 1 & 2) is mostly occupied by the sealed landfill. If possible, it would be quite expensive to protect the liner in order to develop a composting pad on top of the old pile. About two acres are free from solid waste, but the site closure map indicates this area as largely wet land.

Landfill Vicinity Aerial (PDF) -- Landfill Site Closure Map (PDF) -- Letter from Robert Birk, MDEP (PDF)

3. The new Wastewater Treatment Plant Site -- This 5.2-acre lot (tax map 21, lot 11-1) will be mostly occupied by the new WWTP. The parcel may allow space for composting, especially if the sludge generated by the plant is processed there. The town of Wilton has been cited by the Maine Compost School as a good example of a community that composts its own sludge. See links below.

WWTP area map (PDF) -- WWTP site plan (1494 kb PDF)

4. Other City Parcels...

Map of Parcels owned by the City of Ellsworth (PDF)

5. Local Farm -- The MDEP has recommended that we try to hook up with a local farm for composting. Using a farmer who composts for his own use could greatly simplify the approval process. The City would probably still need to have a staging area for collecting and mixing compostables before delivery to a farm for finishing and use.

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Steps to set up and run a compost site:

(Not necessarily in this order!)

1. Obtain local approvals of a site plan and a permit from the State.

2. Create an impervious surface composting pad.

3. Install a fence around the perimeter of the site.

4. Purchase equipment:

-- Front End Loader

-- Tub Grinder

-- Thermometers and miscellaneous

5. Hire a part-time employee

6. Hire a Consultant (typically 2 hours/week - 1 year contract)

7. Budget for labor, fuel and maintenance

8. Arrange for proper "recipe" = 2 parts carbon to 1 part nitrogen (seafood waste)

9. Study how composting could create cost savings and other benefits to the City.

10. If a 40,000 ft2 area could be developed, it would hold approx. 3,300 yards of fresh product. There is shrinkage of 30-50%, yielding about 2,000 yards of final product.

 

 

Related costs to the City in recent years:

2007- Maine Shell Waste 113.22 ton, charge $11,981.08

2008- Maine Shell Waste 158.24 ton, charge $16,683.34

2009- Maine Shell Waste 109.89 ton, charge $11,868.12

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2007- Wood (includes green wood) 264.40 ton, charge $9,241.40

2008- Green 39.21 ton, charge $1,842.87,

2008- Wood 161.39 ton, charge $10,336.71

2009- Green 56.87 ton, charge $2,667.72

2009- Wood 141.08 ton, charge $10,295.92

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Wastewater Treatment Plant Sludge disposal costs consist of hauling and composting by others: (The contract is through June 30, 2013)

year
hauling
composting
total
2008
$13,060
$38,066
$51,126
2009
$14,289
$38,665
$52,954.
2010*
$15,031
$41,672
$56,703

*2010 -- hauled and composted about 620 tons = 730 cubic yards.

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Average Costs:

3 year shellfish waste averages $13,000 cost to the City with average tonnage of 126.

3 year green/wood waste averages $11,000 cost to the City with average tonnage of 220.

Wastewater Treatment Plant sludge disposal costs are about $54,000 per year

Shellfish + Wood + WWTP Sludge = $78,000 per year for disposal

The City n is in a long-term contract with Hawk Ridge through June 30, 2013, but has an "out" clause.

Mike Wellman offered the results of his research into prices for composting carbon ingredients. Sawdust is available for $23 per ton, while wood shavings go for $80 per ton. Mike said that knowing the ratio for the recommended “recipe” would help come up with a more accurate estimate of annual costs.

Municipal Example:

Toby Stephenson learned that Wilton, ME composts 250-300 cubic yards of sewer sludge per year but do not sell the product, they give it away...and even deliver it to residences. Costs are around $40 a cubic yard ($12,000 per year). In contrast, Ellsworth ships out about 620 cu yards at a cost of around $60,000. If we could operate under the same guidelines as the town of Wilton it would cost around $24,800, a savings of $35,200.

Find out more at: The Town of Wilton Recycling and Waste Disposal Web Page .

Commercial Example:

Hawk Ridge charges $55 per ton ($44 per cubic yard) for our sewer sludge, processes it and then sells it as a finished product. They are a subsidiary of New England Organics (and Casella Waste Systems), a much larger company that processes and distributes their own product. Casella's compost material (which includes biosolids) sells for about $15 per yard delivered (about $2 a yard is for delivery). We can't yet project what that puts the sludge market value at because during the compost process there will be some bulk lost, and adding wood/carbon additives at an additional cost will increase bulk. At least for now we know there is a market value for composted biosolids, and after a little research with some local construction companies, I know they would be willing to buy product from the City.

New England Organics and Hawk Ridge in Unity are subsidiaries of Casella Waste Systems, Inc. of Portland. Find out more at: http://www.newenglandorganics.com/services/.

Meeting with Coast of Maine Organics

Feb. 16, 2011-- Several SE members met with Carlos Quijano and learned that:

  • Coast of Maine would like to take Ellsworth's seafood waste, but is not interested in biolsolids or yard waste.
  • The usual deal is "no tipping fee" for compostable materials.
  • Transportation and storage of putrescible waste are still the main problems.
  • Moving small quantities is too expensive.
  • These problems can hopefully be overcome via secure transportation containers, satellite compost piles or pumpable storage tanks.
  • Location of a compost facility is critical, considering convenience and potential odor and other problems.
  • Ellsworth could begin the compost process for seafood residuals by mixing in a carbon source and holding it in a separate, aerated pile until enough is gathered to make the trip to Marion TWP worthwhile.
  • Yarmouth has a sludge compost facility and is similar in size to Ellsworth.

Links:

Maine DEP -- Composting regulations, licensing

State Planning Office: -- Guides to Municipal Composting

State Planning Office: -- Recycling & Composting Workshop materials

University of Maine -- Maine Compost School -List of Maine compost facilities

Compost Production Consulting -- Maine Environmental.Services, Inc.

City of Ellsworth -- Community Gardens page.

Composters: Coast of Maine Organics - Little River Compost - Ocean Organics

Winterwood (Shut down due to disagreements with MDEP. They are in Lyman.)

Molecular encapsulator for sludge disposal -- Moleculoc

Yarmouth Wastewater Department

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